In 1842 he was appointed naturalist to the expedition for surveying the north-east coast of Australia in H.M.S. Fly. This expedition spent four years in surveying the less-known parts of the Australian coast and the islands of Torres Straits, visiting Java, and touching also at New Guinea, where they discovered the river which has since been named the Fly. Jukes devoted himself to the natural history, ethnology, and geology of these regions, and the collections he made were sent to the British Museum. He returned to England in 1846, and soon afterwards joined the staff of the Geological Survey. He was sent into North Wales to work out the complicated structure of that country with Messrs. Ramsay, Forbes, and Aveline. The outdoor work, the invigorating air, the congenial companionship, and the freedom from care and conventionalities, peculiarly suited his tastes, and until 1850 his time was chiefly spent in Wales or Staffordshire. The results of his work were eventually published in the maps, sections, and memoirs of the Geological Survey. Meantime, he prepared a ‘Narrative of the Voyage of H.M.S. Fly’ (1847), and a ‘Sketch of the Physical Structure of Australia’ (1850). In 1850 he was appointed director of the Irish branch of the survey. The responsibilities of this post proved to be heavy; his personal superintendence was required both in the field and at the office in Dublin, and the peculiarities of Irish life and character made both kinds of duty very arduous. But his energy and power of organisation surmounted the difficulties, and he remained director for nineteen years, holding also the post of lecturer on geology at the Royal College of Science, writing many memoirs and papers, and publishing several manuals of geology. During his brief vacations he made geological excursions to Auvergne, the Rhine district, Devon, and Cornwall, conversing and corresponding with most of the leading geologists of the day.
At the meeting of the British Association at Birmingham in 1865 Jukes lectured on the South Staffordshire coal-field, in which he recommended further exploration of the coal-fields which are buried beneath the red rocks of the midland counties, and urged ‘that such an exploration ought to be undertaken at the national expense.’ He was appointed in 1866 a member of the royal commission instituted by parliament to inquire into the resources of our coal-fields. Here his knowledge of the midland coal-fields was of special value.
Jukes died at Dublin on 29 July 1869 in consequence of an injury to the brain, the result of a fall. He married in 1849 a daughter of Mr. J. Meredith of Harborne, Birmingham, who survived him about eleven years. They had no children.
As a field-geologist Jukes had few equals; he had an exceptional faculty of grasping the structure of a district, and of quickly explaining what had puzzled his assistants. He took a prominent part in establishing the Huttonian doctrine that all valleys have been excavated by the action of running water, and that most other features of the earth's surface owe their origin to rain and river work rather than to the agency of the sea or of subterranean forces. As a writer and lecturer his style was clear, vigorous, and direct; personally he was notably upright and straightforward.
His principal works are:
- ‘Excursions in and about Newfoundland,’ 2 vols. 8vo, London, 1842.
- ‘Narrative of the Surveying Voyage of H.M.S. Fly,’ 2 vols. 8vo, London, 1847.
- ‘A Sketch of the Physical Structure of Australia,’ 8vo, London, 1850.
- ‘Popular Physical Geology,’ 12mo, London, 1853.
- ‘The Geology of the South Staffordshire Coal-field,’ ‘Mem. Geol. Survey,’ vol. i. pt. ii. (Records of the School of Mines).
- ‘The Student's Manual of Geology,’ 8vo, Edinburgh, 1st edit. 1857; 2nd 1863; 3rd 1871 (after his death).
- ‘The School Manual of Geology,’ sm. 8vo, Edinburgh, 1863; 5th edit. 1890.
The following are his most important scientific papers: ‘Sketch of the Geology of the County of Waterford,’ ‘Journ. Geol. Soc. Dublin,’ v. 147; ‘On the Structure of the North-eastern part of the County Wicklow’ (with Mr. A. Wyley), ‘Journ. Geol. Soc. Dublin,’ vi. 28; ‘Notes on the Classification of the Devonian and Carboniferous Rocks of the South of Ireland’ (with Mr. J. W. Salter), ‘Journ. Geol. Soc. Dublin,’ vii. 63; ‘On the Mode of Formation of some of the River-Valleys of the South of Ireland,’ ‘Quart. Journ. Geol. Soc.’ xviii. 378; ‘On the Carboniferous Slate and Old Red Sandstone of South Ireland and North Devon,’ ‘Quart. Journ. Geol. Soc.’ xxii. 320; ‘Additional Notes on the Grouping of the Rocks in North Devon and West Somerset’ (read to Geol. Soc. London, but privately printed); ‘Notes on Parts of South Devon and Cornwall,’ ‘Journ. Roy. Geol. Soc. Ireland,’ ii. 67. Forty-two memoirs explanatory of the geological maps of Ireland were edited, and in great part written, by Jukes during the progress of the Irish survey.
[The Letters of J. B. Jukes, edited, with Memorial Notes, by his Sister, London, 1871; obituary notices in the Geological Magazine, 1869; private information.]
